High energy flywheels have potential use in automobiles, homes, or water vehicles. A high energy flywheel would enable the use of a smaller power plant with the flywheel being utilized for supplying the extra energy required for acceleration.
The rim flywheel is traditionally used because of its high energy storage per pound per revolution. This is due to the high moment of inertia caused by a concentration of mass at the outside of the rim flywheel. However, rim flywheels have limitations in their energy storage because of a severe stress concentration at the spoke/rim interface. This is caused by a much greater rim strain in contrast to the spoke strain at high speed.
Multiconcentric rim flywheels have been proposed, however there is a serious drawback to their structural integrity. As the speed of the multiconcentric rim flywheel is increased, the outer rim or rims are subjected to higher stresses for a given material density causing them to expand more than the inner rims. With increased speed the outer rims grow free from the inner rims creating a balance problem as well as containment problems.